The invention relates to a programmable door closer which, depending on the travel and direction, considerably improves the comfort of passing though a door with different transmission ratios and therefore different moment curves. In addition, a method is described for operation of such a door closer.
A method and a system for controlling the force of a closing device can be found in DE 35 35 506 A1. The door is connected by means of a closing device in the form of a door closer and rod arms articulated with one another and mounted thereon being connected with the door frame. The control of the variable force for opening and then automatically closing the door is modified in a suitable fashion by shifting the end of the rod that is remote from the door-closing device, by the moment exerted by the closing device on the door in separate phases of opening and closing of the door. This system is a device that operates on external energy, i.e. an electric motor is provided that displaces a slider and simultaneously determines its position in a guide member. As a result, the motor is controlled in accordance with the desired opening angle.
U.S. Pat. No. 4,979,261 teaches a door closer with a variable articulation position. Because of a gear mounted on the closing shaft, said gear rolling along the door, the point of engagement of the rod and hence the entire moment aspect is automatically changed. The opening force is reduced in this mechanical way while the closing force increases at the same time.
In another U.S. Pat. No. 3,818,637 a device is described that allows rapid opening of a door.
A device that opens a door with a linear force is shown in U.S. Pat. No. 4,231,192. In this case an approximately linear curve of the force on the door as a function of the opening angle is achieved by an appropriate system of levers combined with external energy in the form of a power supply.
A door closer that operates with two pistons can be found in U.S. Pat. No. 4,040,144. This system likewise uses external energy in the form of air.
U.S. Pat. No. 4,419,786 describes a system by which the force required to open a door is reduced relative to normal door opening situations. A door closer is used in this case. By displacement of the remote end of the rod connected with the door closer, beginning at a certain opening angle, the ratio of forces is changed by utilizing additional spring forces and a hydraulic or pneumatic control. As a result, the moment exerted by the door closer on the door through the articulated rod system can be changed. This illustrated principle is very complicated and cannot be used universally with its ability to adapt to a very wide variety of different operating modes.
A device in the form of a door closer that is shown in Swedish disclosure document 469,342 consists of a housing in which two pistons are mounted movably. In addition, two springs are provided, each of which is directly associated with a piston and acts on it in the same direction. The other piston is connected with a piston rod whose rear end is received in a sealing fashion in a central bore of the second piston. The diameters of the two pistons are different. The fluid flow of the damping medium through the pistons is controlled by various channels in conjunction with valves. This measure ensures that the force required for opening the door is low while a high force is available for the end phase of the closing process.
To reduce the opening moment, a solution is known from DE-OS 32 34 319 in which the required higher closing force is supplied by external energy for pretensioning a spring. In this solution, the additional pretensioning of the spring both by an electric motor and also by a piston can be carried out by pressure medium circulation generated by external energy.
The goal of the invention consists in improving a door closer in such fashion that a low opening moment is required when opening the door, while providing for a high closing moment when opening the door. For this purpose, no external energy is to be used like that used in several solutions in the prior art and at the same time a door closer of this kind is to be economical to manufacture and also simple to install.
The goal of the invention is achieved by virtue of the fact that the normally existing permanent connection between the opening and closing forces is eliminated. The permanent coupling is eliminated by virtue of the fact that in addition to the existing door piston, another spring piston is provided that is subjected to the action of the. closing spring. The additional pressure chambers that thus result by contrast to a normal door closer are connected with one another firstly by permanent channels but also by controlled channels or throttles and valves for the damping medium. By this provision and the addition of at least one hydraulic second transmission, the transmission of the force can be controlled. During the opening process and during the subsequent first part of the initial closing process, this additional hydraulic transmission has a force multiplication ratio of U=1. During the further closing process there is a range in which the force multiplication ratio U&lt;1, i.e. the closing moment is reduced. It is only in a third part of the closing process, namely in the range in which the door is to slam shut, that the force multiplication ratio U&gt;1 is reached. This means that the closing moment is greater than the opening moment.
In the embodiment of the idea according to the invention, both the spring piston and the door piston are given an L-shaped design. As a result, there are two displacement surfaces of different sizes. As a result of the geometric design of the displacement surfaces, adaptation and therefore almost a form of programming are possible because the damping medium can be controlled within the door closer housing accordingly as a result. The channels, pockets, throttles, and chambers located inside the door piston and spring piston can be viewed as switching means since they correspond to switching means likewise provided outside the piston. Such a possibility makes it possible for the individual piston chambers to be activated alternately, so that damping can be performed by throttles. An applied pressure can thus be obtained by appropriate check valves in certain circuits.
The hydraulic damping and switching means permit a deliberate and known damped movement of the door piston and the spring piston. For this purpose, according to a method to be specified, a control is performed. A method of this kind for example can proceed such that when the door is opened, which can take place manually or with a power-actuated drive, and during the subsequent closing process which is possible singly and solely by the energy stored in the spring reservoir, up to a door opening angle that is to be determined and hence can be selected individually, the spring piston and the door piston move at the same speed as a result of a pressure equalization between all of the piston chambers filled with the hydraulic fluid. It is only above a certain opening angle of the door that a control can be activated that causes a separation of the door piston from the spring piston. As a result, the door piston moves away from the spring piston, which represents a smaller multiplication ratio. In the final range of the closing process, i.e. in the range in which the door is also intended to engage securely into the latch by means of the striker plate, the two pistons approach one another once again with increased closing force.
With such a method it is possible for the door closer to have, as a function of travel and direction, at least two different multiplication ratios and hence different moment curves. As a result of the idea according to the invention, additional hydraulic transmissions can be interposed in unlimited numbers that would result in an infinite number of different multiplication ratios. Therefore an extremely accurate tuning of the moment curves could be achieved with the invention.
The invention will now be described in greater detail with reference to one possible embodiment shown schematically.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.